The present invention relates in general to high security concealed shackle lock devices for use with paired adjacent staple formations of locking bars or so-called hasps, one or both of which may be L-shaped flange bars, whereby the adjacent alined staple formations receive the shackle therethrough and are surrounded forwardly and in all four lateral directions by the lock body for protection against attack by persons seeking unauthorized forced opening of the locking assembly.
The conventional type of padlock previously used with hasp and staple assemblies for locking doors, security containers and the like was of the exposed shackle type which usually included a U-shaped shackle formed of a pair of spaced parallel straight legs joined by a curved intermediate portion, together with a padlock body provided with a key lock plug or combination locking mechanism and bolt means within the padlock body for interlocking with grooves or notches in the shackle leg portions which extend into shackle sockets or openings in the padlock body. In the locked position, the exposed U-shaped shackle normally extends in exposed upstanding relation from the padlock body and is thus exposed to attack by cutting instruments or other burglary tools. In many applications where padlocks have been previously used, the padlock was in an exposed environment where it was not under constant supervision by security personnel, watchmen, or people charged with protecting the area in which the lock was located. In such exposed or unsupervised padlock situations, a person seeking unauthorized entry into the space secured by the padlock had the opportunity to open the lock by any of a number of conventional techniques, such as picking, rapping, sawing, or forcing the padlock open by inserting a wedge type tool between the hasp members and padlock body or shackle to wedge or chisel the lock open.
In recent years, much effort has been devoted to improving lock security for the security enclosures in such exposed situations, by providing a pair of steel plate locking bar members, for example a pair of L-shaped steel locking bars or a paired L-shaped steel locking bar and a straight locking bar, each having a foot or base portion to be fastened by tamper-resisting screws to adjacent mounting surfaces of a pair of doors, or of a door and door jamb or comparable surface, and the plates each providing an integral outwardly projecting apertured end portion serving as a staple formation or hasp, hereinafter usually referred to as the hasp portion, to be disposed in mated or laterally alined relation and secured by a hardened high security padlock shackle or similar locking bolt. To further improve security, the number of pin tumblers or levers employed in the key cylinder or key locking plug of such padlocks has been increased and the key cylinder made to resist drilling, picking and similar attack techniques. To protect the shackle against attack from the sides and from all directions by sophisticated cutting instruments, hardened padlock bodies have been developed having shroud formations which shield the sides and front of the shackle from attack by cutting instruments.
In some of such locks, the shackle is completely recessed in the padlock body in locking position and the shackle recess has a rearwardly opening slot to receive the pair of outwardly projecting apertured hasp portions of the locking bars with the shackle or bolt passed through the apertures in the hasp portions interfitted into the rearwardly opening recess of the lock body. Examples of padlocks of the shrouded type and of other lock devices designed for use with similar locking bars are found in prior U.S. Pat. Nos. 3,652,114 to Cady, 3,759,557 to Athas, 3,769,821 and 3,817,062 to Randel, 3,858,923 to Bunn, 3,901,058 and 3,996,774 to Best, 3,744,280 to Brown and 3,638,460 to Berry. FIG. 8 of U.S. Pat. No. 3,710,603 and FIG. 10 of U.S. Pat. No. 3,713,309 to Miller, both assigned to the assignee of the present application, also show shrouded shackle padlocks with a cruciform shaped recess in the upper end portion of the padlock body opening rearwardly to receive the laterally juxtaposed forwardly projecting apertured hasp portions of such locking bars.
A particular problem with these L-shaped flange type locking bars secured by padlock or enshrouding lock devices has been the ability of burglars or unauthorized persons to force the lock off of the locking bars by driving a wedge down between the rear portion of the lock body and the locking bars and thereby tear the shackle through the ear or staple portion of the locking bars and thereby destroy the holding action of the lock on the locking bars.
An object of the present invention is the provision of a novel attack-resistant concealed shackle lock construction for use with L-shaped locking bars or the like constructed with a rearwardly opening cavity to receive apertured hasp portions of the locking bars and a knuckle type attack resisting device so that attack on the lock mechanism with wedges to attempt to force it off the apertured hasp portions will further increase binding action of the lock mechanism components on the apertured hasp portions as the wedges are driven, providing additional strength and support to the locking bar hasps and shackle.
Another object of the present invention is the provision of a novel attack-resisting concealed shackle lock of the type described in the preceding paragraph, wherein the lock body is provided with a movable pivoted knuckle device having a hasp-binding surface adjacent the locking bar hasp portions to tightly bind the latter against an opposite surface of the hasp-receiving cavity and lend additional strength and support to the hasp portions for resisting ripping of the shackel from the locking bars.
Yet another object of the present invention is the provision of a novel shackle type locking device of the concealed shackle type as described in the preceding paragraph, wherein progressively tighter grasping or binding against the hasp portions is achieved responsive to movement of a wedge relative to the lock body during attempted forced entry by wedge attack, more than usual protective metal is provided around the hasps deterring saw attack, and an operating cyclinder surrounds the key lock plug to provide maximum security against picking and operate the shackle between locking and unlocking positions, and when in locked position, the cylinder is enclosed in protected relation with the lock body.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.